That quote could only ever have been written by a tank. Substitute tank for quarterback and encounters for games and you see how this argument is not without its share of ego and hot air. But there are good points to the argument too. On the one hand, paladins and, to a lesser extent druids, really are much better equipped for multi-mob tanking, making warriors the third choice for heroics. On the other hand, both druids and paladins have reasonable cause for concern at the severe shortage of hybrid tanking gear in end game, on top of the fact that very high-end content in 25 man raids seems poorly designed for hybrid tanks.
Without a high-end tanking character, I'm hardly one to comment. My only concern is that tanks are encouraged, not discouraged, because we need more of them not less. Anything which makes druids and paladins feel they need to respec to keep a raid spot or forces warriors out of pve and into the arean is a Bad Thing.
Now maybe Blizzard is aware of the problem and working on it. Death Knights will be capable of tanking, so we are told, and a new style of play may encourage more people to take up the tanking role. Or it could just cause further animosity among a player base already feeling un loved and under pressure.
This is a long term problem which we can only hope Blizzard is working on for the expansion. In the mean time, throw your tank some love every now and them, just make sure it doesn't go to their head.